Most parti-colored refers to an object or person that is boldly or diversely multi-colored. The antonyms for the term would be words like monochromatic, plain, homogenous, uniform, or simple. A monochromatic object has only one color, whereas a plain object is devoid of any patterns or designs. Homogenous refers to sameness, yielding one color or pattern, while a uniform object is of one particular color throughout. Finally, a simple object is characterized by simplicity, which suggests that it is not multi-colored. Thus, the antonyms for "most parti-colored" offer a range of words that range from the most basic to those indicating uniformity.